(Newser)
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Berlin prosecutors said an autopsy today showed that Thomas Doerflein, the zookeeper who gained fame for hand-rearing the polar bear cub Knut, died of a heart attack. The city's mayor paid tribute to him for writing Berlin history. "Other causes of death, in particular involvement by another party, are ruled out from a medical point of view," Berlin prosecutors said.

Doerflein's death was frontpage news in German newspapers today. Berlin's BZ tabloid, under the headline "Knut's daddy dead," dedicated 11 pages to the keeper, while the Berlin zoo set up an online condolence book. Knut became a worldwide sensation when the Berlin Zoo decided to raise him by hand, and Doerflein was on hand at every stage of the bear's growth.